Baoyu and Daiyu are in Xiangyun's next home and last home respectively. She signed up to drink * * * at the next home, metaphorically making a cup. I think this is the fact that Cao Gong wrote down their engagement with a hidden pen. We can also find clues from many places in the book. Let's not talk about this. Let's talk about this.
This is called a "banquet". Daiyu is not used to it, so she will drink it carefully. Besides, the book says that she has to take medicine when she goes back, and both medicine and wine have to be solved. Naturally, she "knows her heart but can't do it". As soon as everyone saw Baoyu, she poured the wine into the spittoon.
Baoyu didn't drink, but drank half. Before Fang Guan said that he would "give up drinking", Baoyu gave it to Fang Guan. The square crown looked up and gulped it down, showing the heroic spirit of the square crown. The book also said that Baoyu gave her a "son's name": Xiongnu, Lu Ye, which later seemed to be changed to glass. This can explain her "masculine color" or the embodiment of tomboy.
Neither Baoyu nor Daiyu drank this wine by accident. I don't think they want to lose their manners in front of everyone and give them a chance to joke. But if they don't drink this wine, they may not be able to drink it. Opportunities don't always exist. Baodai thought she could be together forever, but there was nothing she could do without the help of the old man under the moon.